Integral 1 to 2 of (x^3)lnxdx

What do we use as u? I tried lnx and x^3 and it didnt seem to work.

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- March 4th 2013, 01:53 PMSteelers72Definite integral with u substitution
Integral 1 to 2 of (x^3)lnxdx

What do we use as u? I tried lnx and x^3 and it didnt seem to work. - March 4th 2013, 02:39 PMBobPRe: Definite integral with u substitution
The method is to integrate by parts.

- March 4th 2013, 05:26 PMhollywoodRe: Definite integral with u substitution
You should remember the acronym LIATE: you want to choose for u whatever comes first in the list Logarithmic, Inverse trigonometric, Algebraic, Trigonometric, Exponential. In this case you would choose .

- Hollywood - March 4th 2013, 08:49 PMSteelers72Re: Definite integral with u substitution
- March 4th 2013, 11:36 PMsbhatnagarRe: Definite integral with u substitution
Here's another method:

Differentiate with respect to :

Putting , gives the answer